Abstract: With the acceleration of urbanization and the continuous growth of population, the problem of non-point source pollution caused by rainfall runoff is becoming increasingly prominent. The Xuebu River Basin in Jintan District, Changzhou City was taken as an example, this paper constructed a hydrological and water quality model suitable for the study area based on the SWMM model, analyzed the change process of non-point source pollution in the study area under different rainfall conditions by designing rainfall scenarios with different return periods, and simulated and analyzed the water level and water quality of the Sanxingqiao section of the Xuebu River in 2022 and the pollution load of each sub-catchment area. The results showed that compared with the upstream and downstream of the Xuebu River, the pollution in the middle reaches of the Xuebu River was more serious, and cultivated land was the land use type with more non-point source pollution load. As the intensity of rainfall increases, the pollution load will increase, and the peak of pollutant concentration will also be advanced. The results of this study can provide theoretical basis and technical support for the determination of the contribution of Jintan to local water pollution in the process of urbanization and its pollution control.